title: Oestradiol and progesterone receptors in the mammary tissue and tumours of female Holtzman rats following 7,12-dimethylbenz(a)anthracene administration.
abstract: A single dose of the carcinogen 7,12-dimethylbenz(a)-anthracene (DMBA) when administered to 55-day-old female Holtzman rats did not produce any change in the pattern or amount of oestradiol receptors in the breast tissues, when compared to age-matched control animals. The period of observation extended up to 280 days of age. Following DMBA administration to 102 animals, only 60% developed carcinomas of the breast, of which 59 and 50% were ER- an PgR-positive, respectively. This lower yield of steroid receptor-positive tumours in this strain of rats was also reflected in a very low incidence of regression of tumours to ovariectomy. Plausible explanations for both these findings have been offered.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology*; D000232:Adenofibroma / Q000139:chemically induced / Q000378:metabolism; D000818:Animals; D001551:Benz(a)Anthracenes / Q000494:pharmacology*; D002369:Castration; D005260:Female; D006801:Humans; D008321:Mammary Glands, Animal / Q000378:metabolism; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000378:metabolism*; D009376:Neoplasms, Hormone-Dependent / Q000378:metabolism; D051381:Rats; D011960:Receptors, Estrogen / Q000187:drug effects*; D011980:Receptors, Progesterone / Q000187:drug effects*
chemical_list: D001551:Benz(a)Anthracenes; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D015127:9,10-Dimethyl-1,2-benzanthracene